Any of the elongated contractile threads found in striated muscle cells.
- ‘Individual muscle cells are extremely elongated and enclose many-stranded cables woven from threads called myofibrils.’
- ‘In cross section, skeletal muscle fibers are seen to be composed of numerous small aggregates of contractile substance, the myofibrils.’
- ‘Inside the fibre are the myofibrils, which constitute the contractile apparatus, and a system for controlling the myofibrils through changes in calcium concentration.’
- ‘Briefly, the cardiac myofibrils are composed of the major contractile proteins, actin and myosin.’
- ‘The number of myofibrils within the enlarged muscle fiber can increase more than 10-fold.’